[ekohl] 16686: Make IoGetDeviceObjectFromDeviceInstance work without using the Registry. (experimental)

Make IoGetDeviceObjectFromDeviceInstance work without using the
Registry. (experimental)
Modified: trunk/reactos/ntoskrnl/io/plugplay.c
  _____  

Modified: trunk/reactos/ntoskrnl/io/plugplay.c
--- trunk/reactos/ntoskrnl/io/plugplay.c	2005-07-21 20:10:47 UTC
(rev 16685)
+++ trunk/reactos/ntoskrnl/io/plugplay.c	2005-07-21 20:30:55 UTC
(rev 16686)
@@ -224,8 +224,35 @@

 
 
 static PDEVICE_OBJECT
+IopTraverseDeviceNode(PDEVICE_NODE Node, PUNICODE_STRING
DeviceInstance)
+{
+    PDEVICE_OBJECT DeviceObject;
+    PDEVICE_NODE ChildNode;
+
+    if (RtlEqualUnicodeString(&Node->InstancePath,
+                              DeviceInstance, TRUE))
+        return Node->PhysicalDeviceObject;
+
+    /* Traversal of all children nodes */
+    for (ChildNode = Node->Child;
+         ChildNode != NULL;
+         ChildNode = ChildNode->NextSibling)
+    {
+        DeviceObject = IopTraverseDeviceNode(ChildNode,
DeviceInstance);
+        if (DeviceObject != NULL)
+        {
+            return DeviceObject;
+        }
+    }
+
+    return NULL;
+}
+
+
+static PDEVICE_OBJECT
 IopGetDeviceObjectFromDeviceInstance(PUNICODE_STRING DeviceInstance)
 {
+#if 0
     OBJECT_ATTRIBUTES ObjectAttributes;
     UNICODE_STRING KeyName, ValueName;
     LPWSTR KeyNameBuffer;
@@ -308,7 +335,7 @@
     ZwClose(ControlKeyHandle);
     if (!NT_SUCCESS(Status))
     {
-        DPRINT1("Failed to open the 'Control' key (Status %lx)\n",
Status);
+        DPRINT1("Failed to query the 'DeviceReference' value (Status
%lx)\n", Status);
         return NULL;
     }
 
@@ -336,9 +363,30 @@
     DPRINT("IopGetDeviceObjectFromDeviceInstance() done\n");
 
     return DeviceObject;
+#endif
+
+    if (IopRootDeviceNode == NULL)
+        return NULL;
+
+    if (DeviceInstance == NULL ||
+        DeviceInstance->Length == 0
+        )
+    {
+        if (IopRootDeviceNode->PhysicalDeviceObject)
+        {
+            ObReferenceObject(IopRootDeviceNode->PhysicalDeviceObject);
+            return IopRootDeviceNode->PhysicalDeviceObject;
+        }
+        else
+            return NULL;
+    }
+
+    return IopTraverseDeviceNode(IopRootDeviceNode, DeviceInstance);
+
 }
 
 
+
 static NTSTATUS
 IopGetDeviceProperty(PPLUGPLAY_CONTROL_PROPERTY_DATA PropertyData)
 {